在android下一个活动的视频视图中传输录制的摄像机视频（使用媒体录像机）
如何在下一个活动中传输摄像机录制的视频，并在点击下一个活动的视频视图时播放视频 摄像机功能通过使用媒体记录器来执行 当尝试在空对象引用（根据日志）上调用虚拟方法“android.net.Uri android.content.Intent.getData（）”时，当前存在NullPointerException。 如何解决这个问题。 这是我的代码： 第一项活动在android下一个活动的视频视图中传输录制的摄像机视频（使用媒体录像机）,android,android-intent,android-camera,uri,surfaceview,Android,Android Intent,Android Camera,Uri,Surfaceview,如何在下一个活动中传输摄像机录制的视频，并在点击下一个活动的视频视图时播放视频 摄像机功能通过使用媒体记录器来执行 当尝试在空对象引用（根据日志）上调用虚拟方法“android.net.Uri android.content.Intent.getData（）”时，当前存在NullPointerException。 如何解决这个问题。 这是我的代码： 第一项活动 public class AndroidVideoCaptureExample extends Activity { priva
public class AndroidVideoCaptureExample extends Activity {
private Camera mCamera;
private CameraPreview mPreview;
private MediaRecorder mediaRecorder;
private Button capture, switchCamera;
private Context myContext;
private LinearLayout cameraPreview;
private boolean cameraFront = false;
String mFileName;
Intent mediaIntent;
boolean isPlaying = false;
Uri url;
long maxduration = 10000;
SurfaceHolder holder;
Uri videoUri;
private static final int CAMERA_CAPTURE_VIDEO_REQUEST_CODE = 200;
// for timer
private TextView timerValue;
private long startTime = 0L;
private Handler customHandler = new Handler();
long timeInMilliseconds = 0L;
long timeSwapBuff = 0L;
long updatedTime = 0L;
MediaPlayer mediaPlayer;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
myContext = this;
initialize();
}
private int findFrontFacingCamera() {
int cameraId = -1;
// Search for the front facing camera
int numberOfCameras = Camera.getNumberOfCameras();
for (int i = 0; i < numberOfCameras; i++) {
CameraInfo info = new CameraInfo();
Camera.getCameraInfo(i, info);
if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
cameraId = i;
cameraFront = true;
break;
}
}
return cameraId;
}
private int findBackFacingCamera() {
int cameraId = -1;
// Search for the back facing camera
// get the number of cameras
int numberOfCameras = Camera.getNumberOfCameras();
// for every camera check
for (int i = 0; i < numberOfCameras; i++) {
CameraInfo info = new CameraInfo();
Camera.getCameraInfo(i, info);
if (info.facing == CameraInfo.CAMERA_FACING_BACK) {
cameraId = i;
cameraFront = false;
break;
}
}
return cameraId;
}
public void onResume() {
super.onResume();
if (!hasCamera(myContext)) {
Toast toast = Toast.makeText(myContext, "Sorry, your phone does not have a camera!", Toast.LENGTH_LONG);
toast.show();
finish();
}
if (mCamera == null) {
// if the front facing camera does not exist
if (findFrontFacingCamera() < 0) {
Toast.makeText(this, "No front facing camera found.", Toast.LENGTH_LONG).show();
switchCamera.setVisibility(View.GONE);
}
mCamera = Camera.open(findBackFacingCamera());
mPreview.refreshCamera(mCamera);
}
}
public void initialize() {
cameraPreview = (LinearLayout) findViewById(R.id.camera_preview);
mPreview = new CameraPreview(myContext, mCamera);
cameraPreview.addView(mPreview);
capture = (Button) findViewById(R.id.button_capture);
capture.setOnClickListener(captrureListener);
switchCamera = (Button) findViewById(R.id.button_ChangeCamera);
switchCamera.setOnClickListener(switchCameraListener);
timerValue = (TextView) findViewById(R.id.timer);
}
OnClickListener switchCameraListener = new OnClickListener() {
@Override
public void onClick(View v) {
// get the number of cameras
if (!recording) {
int camerasNumber = Camera.getNumberOfCameras();
if (camerasNumber > 1) {
// release the old camera instance
// switch camera, from the front and the back and vice versa
releaseCamera();
chooseCamera();
} else {
Toast toast = Toast.makeText(myContext, "Sorry, your phone has only one camera!", Toast.LENGTH_LONG);
toast.show();
}
}
}
};
public void chooseCamera() {
// if the camera preview is the front
if (cameraFront) {
int cameraId = findBackFacingCamera();
if (cameraId >= 0) {
// open the backFacingCamera
// set a picture callback
// refresh the preview
mCamera = Camera.open(cameraId);
// mPicture = getPictureCallback();
mPreview.refreshCamera(mCamera);
}
} else {
int cameraId = findFrontFacingCamera();
if (cameraId >= 0) {
// open the backFacingCamera
// set a picture callback
// refresh the preview
mCamera = Camera.open(cameraId);
// mPicture = getPictureCallback();
mPreview.refreshCamera(mCamera);
}
}
}
@Override
protected void onPause() {
super.onPause();
// when on Pause, release camera in order to be used from other
// applications
releaseCamera();
}
private boolean hasCamera(Context context) {
// check if the device has camera
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
return true;
} else {
return false;
}
}
boolean recording = false;
OnClickListener captrureListener = new OnClickListener() {
@Override
public void onClick(View v) {
if (recording) {
String extension = MimeTypeMap.getFileExtensionFromUrl(mFileName);
String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
Intent mediaIntent = new Intent(Intent.ACTION_VIEW);
mediaIntent.setDataAndType(Uri.parse(mFileName), mimeType);
startActivityForResult(mediaIntent,CAMERA_CAPTURE_VIDEO_REQUEST_CODE);
// stop recording and release camera
mediaRecorder.stop(); // stop the recording
releaseMediaRecorder(); // release the MediaRecorder object
Toast.makeText(AndroidVideoCaptureExample.this, "Video captured!", Toast.LENGTH_LONG).show();
recording = false;
} else {
if (!prepareMediaRecorder()) {
Toast.makeText(AndroidVideoCaptureExample.this, "Fail in prepareMediaRecorder()!\n - Ended -", Toast.LENGTH_LONG).show();
finish();
}
// work on UiThread for better performance
runOnUiThread(new Runnable() {
public void run() {
// If there are stories, add them to the table
try {
mediaRecorder.start();
} catch (final Exception ex) {
// Log.i("---","Exception in thread");
}
}
});
recording = true;
}
startTime = SystemClock.uptimeMillis();
customHandler.postDelayed(updateTimerThread, 0);
}
};
private Runnable updateTimerThread = new Runnable() {
public void run() {
timeInMilliseconds = SystemClock.uptimeMillis() - startTime;
updatedTime = timeSwapBuff + timeInMilliseconds;
int secs = (int) (updatedTime / 1000);
int mins = secs / 60;
secs = secs % 60;
int milliseconds = (int) (updatedTime % 1000);
timerValue.setText("" + mins + ":"
+ String.format("%02d", secs));
customHandler.postDelayed(this, 0);
}
};
private void releaseCamera() {
// stop and release camera
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
private void releaseMediaRecorder() {
if (mediaRecorder != null) {
mediaRecorder.reset(); // clear recorder configuration
mediaRecorder.release(); // release the recorder object
mediaRecorder = null;
mCamera.lock(); // lock camera for later use
}
}
private boolean prepareMediaRecorder() {
mediaRecorder = new MediaRecorder();
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
String i = sdf.format(new Date());
mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
mFileName += "/audiorecordtest" + i + ".mp4";
mCamera.unlock();
mediaRecorder.setCamera(mCamera);
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mediaRecorder.setMaxDuration((int) maxduration);
mediaRecorder.setVideoSize(640, 480);
mediaRecorder.setVideoFrameRate(90);
mediaRecorder.setVideoEncodingBitRate(3000000);
// mediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED()
mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
mediaRecorder.setOutputFile(mFileName);
try {
mediaRecorder.prepare();
} catch (IllegalStateException e) {
releaseMediaRecorder();
return false;
} catch (IOException e) {
releaseMediaRecorder();
return false;
}
mediaRecorder.setOnInfoListener(new MediaRecorder.OnInfoListener() {
@Override
public void onInfo(MediaRecorder mr, int what, int extra) {
if (what == MediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED) {
String extension = MimeTypeMap.getFileExtensionFromUrl(mFileName);
String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
Intent mediaIntent = new Intent(Intent.ACTION_VIEW);
mediaIntent.setDataAndType(Uri.parse(mFileName), mimeType);
startActivityForResult(mediaIntent,CAMERA_CAPTURE_VIDEO_REQUEST_CODE);
mediaRecorder.stop();
if (mediaPlayer.isPlaying()) {
mediaPlayer.reset();
}
mediaPlayer.setDisplay((SurfaceHolder) mPreview);
try {
mediaPlayer.setDataSource(mFileName);
mediaPlayer.prepare();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
mediaPlayer.start();
}
}
});
return true;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode==CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {
videoUri = data.getData(); // get the uri of video from intent
launchUploadActivity1(true,videoUri);
//
// }
}
}
private void launchUploadActivity1(boolean isPlaying, Uri uri) {
Intent i = new Intent(AndroidVideoCaptureExample.this, SecondLast.class);
// i.setData(uri); // set the uri to intent
i.putExtra("play",videoUri);
startActivity(i);
}
}
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
MediaPlayer mediaPlayer;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
mHolder = getHolder();
mHolder.addCallback(this);
// mHolder.setFixedSize(176, 144);
mediaPlayer = new MediaPlayer();
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
try {
// create the surface and start camera preview
if (mCamera == null) {
assert mCamera != null;
mCamera.setPreviewDisplay(holder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
}
} catch (IOException e) {
Log.d(VIEW_LOG_TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void refreshCamera(Camera camera) {
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
setCamera(camera);
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
} catch (Exception e) {
Log.d(VIEW_LOG_TAG, "Error starting camera preview: " + e.getMessage());
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
refreshCamera(mCamera);
}
public void setCamera(Camera camera) {
//method to set a camera instance
mCamera = camera;
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
mCamera.release();
mHolder.getSurface();
}
}
我当前的代码根据要求录制了视频，并在录制后播放。但在第二个活动中，它什么也不做。在活动的onActivityResult方法中，获取uri并将其发送到上载活动：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode==CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {
launchUploadActivity1(true);
if (resultCode == RESULT_OK) {
// video successfully recorded
// launching upload activity
Uri videoUri = data.getData(); // get the uri of video from intent
launchUploadActivity1(true,videoUri);
}
}
}
private void launchUploadActivity1(boolean isPlaying, Uri uri) {
Intent i = new Intent(AndroidVideoCaptureExample.this, SecondLast.class);
i.setData(uri); // set the uri to intent
startActivity(i);
}
protected void onCreate(Bundle b){
super.onCreate(b);
Uri videoUri = getIntent().getData(); // do anything from the Uri
}
您可以将意图中视频的Uri传递给另一个活动。我想要一些示例，因为我已经尝试了一些我知道您可以在代码中看到的事情。调试帮助问题需要根据。你的代码不是最小的。请回答您的问题，以确保您的代码是最小的（只有在您的问题中重现您的问题所需的代码）、完整的（用户不需要任何其他内容重现您的问题）和可验证的（提供的代码确实重现了您正面临的问题）。既然如此，您的问题与堆栈溢出无关。请注意，这也是一种常见的情况。这仅适用于所有场景，播放视频后仍会停止扫描，请详细说明？java.lang.RuntimeException:无法传递结果ResultInfo{who=null，request=200，result=0，data=null}到活动camlimit.AndroidVideoCaptureExample}:java.lang.NullPointerException:尝试对空对象引用调用虚拟方法“android.net.Uri android.content.Intent.getData（）”！您正在通过摄影机对象录制视频。从录制的视频发送uri作为数据首先从您的相机活动，然后只有你会得到它那里！
protected void onCreate(Bundle b){
super.onCreate(b);
Uri videoUri = getIntent().getData(); // do anything from the Uri
}